Electrical conductor



May 25, 1937. E. D. BENT ET AL ELECTRICAL CONDUCTOR Filed NOV. 15, 1934INVENTORS E. 0. BENT M. H. EASTLAKE Y QRMM A T TORNE Y Patented May 25,1937 UNITED STATES PATEN'E' OFFICE ELECTRICAL CONDUCTOR porated, NewYork, New York N. Y., a corporation of Application November 13, 1934,Serial No. 752,822

8 Claims.

may often be exposed to unusual conditions of external heat andmoisture.

One object of the present invention is to provide a conductor having amultilayered sheath which is in high degree moisture proof and fireproofand which is both flexible and durable.

One embodiment of the invention contemplates 9, method and its productwhich comprises taking a bare metallic conductor strand, applying asheath of natural wool fibre, impregnating the wool sheath with amoisture proofing ma terlal such as asphalt, coating the impregnatedsheath with stearin pitch or the like, covering the stearin pitchcaating with mica dust, applya layer of asbestos fibre strands over theadhesive, applying a thin fiour paste solution to the-braided asbestossheath and polishing the surface. In some instances a textile outersheath may be braided over the whole.

Other objects and'zfeatures of the invention will appear from thefollowing detailed description of one embodiment thereof taken inconnection with the appended drawing which represents the partiallyuncovered end of a conductor constructed in accordance with theinvention.

In the embodiment of the invention herein disclosed, a metal conductivestrand l0 forms the core of the cord. This strand in may be a bare '4solid wire as shown or may be an intertwisted or interbraided bundle offine wires.

As here disclosed, two fiat strands or tapes ll of wool fibre are woundor served on the core, one over the other with opposite spiraldirections, to form a double layer'of wool sheathing. This layer mightalso be formed by braiding woolen strands instead of serving woolentapes or ends. In some instances it may be advantageous to treatthe'wool before serving or braiding with a preservative solution, as forexample with a 16% solution of glycerol which renders the wool fibresmore resistant to disintegration under heat.

The wool sheath II is then impregnated with waterproofing material suchas asphalt, gilsonite, rosin and rosin oil, or the like as indicated atI2.

ing a thin coating of adhesive thereto, braiding A layer I3 of stearinpitch or the like is applied over the asphalt impregnated wool whichcovers the tackiness of the asphalt, adds to the moisture proof qualityof the sheathing and is flame proof in itself to a considerable degree.

The stearin pitch may then be coated with mica dust or otheranti-sticking material as indicated at M, to further cover any tackinessand to prevent adjacent coils from sticking or quasi welding togetherduring further handling in manufacture.

A thin coating l5 of an adhesive material such as mucilage for exampleis then applied over the mica dusted or plain stearin pitch and a sheathl6 of asbestos fibre yarns is applied thereover preferably by braidingalthough this may also be served .on or otherwise applied, as forexample by felting.

The asbestos covering is then wet with a polishing paste such as amixture of one volume of wheat flour with ten volumes of boiling water,or a 10% solution of alum in water, or other appropriate material, andis compactedand polished as at IT by a rotary polishing machine or otherappropriate means.

In some instances the conductor thus made is then ready for use. Inother instances a mechanically protecting final outer sheath of textilefibres may be applied over the asbestos, preferably by braiding. Also insome instances the coating of the stearin pitch with mica dust may beomitted especially where the conductor is not coiled before the adhesiveand the asbestos are applied. Furthermore in some instances the ad-'hesive between the stearin pitch and the asbestos may be dispensed with.However, in the preferred procedure all the steps are included.

The embodiment of the invention herein disclosed is illustrative merelyand may be modified and departed from in many ways without departingfrom the scope and spirit of the invention as pointed out in and claims.

What is claimed is:

1. As a new article of manufacture, an electrical conductor comprising ametallic conductive core, a cover thereon of wool fibres imDreS- natedwith moisture proof material, a layer of fire proofing material over theimpregnated wool cover, and a sheath of asbestos fibres thereover.

2. As a new article of manufacture, an electrical conductor comprising ametallic conduclimited only by the appended tive core, a cover thereonof wool fibres treated over the impregnated wool cover, and a sheath ofasbestos fibres thereover.

3. As a new article of manufacture, an elec* trical conductor comprisinga metallic conductive core, a cover thereon of wool fibres impregnatedwith asphalt, a layer thereover of stearin pitch, and a sheath ofasbestos fibres thereover.

4. As a new article of manufacture, an electrical conductor comprising ametallic conductive core, a cover thereon of wool fibres impregnatedwith asphalt, a layer thereover of stearin pitch, a coating of mica dustthereon, and a sheath of asbestos fibres thereover.

5. As a new article of manufacture, an electrical conductor comprising ametallic conductive core, a cover thereon of wool fibres impregnatedwith moisture proof material, a layer of fire proofing material over theimpregnated wool cover, a sheath of asbestos fibres thereover, and anouter sheath oi textile strands over the whole.

6. As a new article of manufacture, an elec- 7. As a new article ofmanufacture, an electrical conductor comprising a metallic conductivecore, a cover thereon of wool fibres impregnated with asphalt, a. layerthereover of stearln pitch, a sheath of asbestos fibres thereover, andan outer sheath of textile strands over the whole.

8. As a new article of manufacture, an electrical conductor comprising ametallic conductive core, and a cover thereon of wool fibres treatedwith glycerol to render the same heatresistant.

EDGAR D. BENT.

WILLIAM H. EAS'ILAKE.

